In this video lecture, the educator explains the Epithelium and it domains, starting with the definition of Epithelium. It is one of the four basic types of tissues along with muscle, nervous and connective tissue. It’s a type of tissue which lines the body cavities and hollow structures that include blood vessels, tubular lumen, GIT etc. Characteristics of Epithelial Tissue includes Forming continuous sheets, Apical Surface, Basement Membrane, Avascularity and Regenerate & repair quickly. Functions of Epithelial tissues are Protection, Absorption, Filtration, and Secretion. Then with the help of diagram the types of epithelium tissues are explained in detail.
Surface specializations of epithelial cells are morphologic adaptations for specific functions, are located at, on and/or within plasma membrane domains. Microvilli are cell membrane evaginations that greatly increase surface area for absorption and secretion. Cillia are Cell membrane projections of cytoplasm. Glycocalyx refers to a carbohydrate-rich, covering on the apical surface of certain epithelial cells. Zonula Occludens present on the lateral cell surfaces just beneath the apical pole. Macula Adherens is explained with the help of diagram.
Macula communicans is a junctional area between adjacent cells that facilitates intercellular communication by allowing the passage of small molecules and ions across the narrow intercellular gap through a multitude of junctional pores. The basement membrane is composed of two layers, the basal lamina and the underlying layer of reticular connective tissue. The underlying connective tissue attaches to the basal lamina with collagen VII anchoring fibrils and fibrillin microfibrils. The two layers together are collectively referred to as the basement membrane.